The process of generating electricity can generate a variety of waste wastes that include cooling and process waters that have the potential to release pollutants into surface waters when discharged. These wastewaters can originate from, the following activities that may or may not be found at your school’s power plant:

• Blowdown from flue gas desulfurization
• Once-through cooling water
• Cooling tower blowdown
• Boiler blowdown
• Metal and boiler cleaning waste
• Demineralizer regenerant

Prior to the discharge of wastewaters to either to either surface water bodies or to Publicly Owned Treatment Works (POTW), they need to be acceptable for discharge; which means, their temperature and composition may need to be controlled. To that end, chemicals may need to be added to control for pH and metals. Controls are imposed on these additives and on the temperature of the water being discharged, to ensure that the receiving bodies are not adversely affected. In general if the water is discharged directly to surface water a National Pollutant Discharge Elimination System (NPDES) permit is required. If the water is discharge to a POTW, a local sewer permit governs effluent discharge criteria.

You’ll learn more about the environmental laws; regulations and best practices associated with water treatment additives as you proceed with this section of the EVC tour.